Convection current refrigerator



2 Sheets-Sheet 1 uw w 4ull' v Filed Feb. 21, 194i 'CONVECTI-ON CURRENT RFRIGERATOR July-121,- 1942.

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14, 1942- G.4 OfR. LINDGEN v l2,289,662

CONVECTION CURRENT REFRIGERATOR Patented. July 14, 1942 CoNvEc'rroN CURRENT' aEFaIGEaATon George Oscar Rudolph Lindgren, Galesburg, IIL,

assignor to Outboard, Marine and Manufacturing Company, Waukegan, lli., a corporation of Delaware Application February 2l, 1941, Serial No. 379,955 i iz claims. (ci. sz-ss) My invention 'relates to improvements in refrigerators, with particular reference to refrigerators of a domestic vtype employing gravity circulation of convection'currentsl in a cyclic path orpaths including a chilling unit and one or more food storage chambers enveloped by such currents.

My object is to provide an improved refrigerator of the ydescribed type, in which food ma terials may be stored at different temperatures and protected against dehydration in cases where v such protection is desired, and in which the desired temperatures in different zones or chambers may be accurately maintained by convection currents dependent upon gravity circulation.

More particularly, my objects are to provides, refrigerator cabinet with a set of storage cham- 'bers assembled within the cabinet in spaced relation to some of the walls thereof in such. a` n manner as to provide means for accurately maintaining selective temperatures. within the respective chambers through gravity circulation along line 1-1.

Figure 4 is a plan view, in partial section, of the device shown in Figure 3, taken along line 4 1. n Figure 5 is'a plan view, in partial section, -along line 5 5 of Figure 3. p

Figure 6 is a plan view of an alternate embodiment of the invention, showing the top wall removed to disclose the evaporator unit construction.

Figure 7 is a vertical section of the upper portion of the refrigerator shown in Figure 6, taken Figure 8 is a front elevation of the refrigerator shown in Figure 6, with the freezing compartment door removed.

Like parts are identified by the same reference characters throughout the specification land drawings, and in the modification the corre` sponding parts are identified by the same numbers with a reference letter added. Various other modifications are contemplated, and nothing in the description or drawings is intended to imply of convection currents; to-provide means where- `by storage chambers intended to be-kept at low temperatures may be associated with a chilling unit in one compartment of a cabinet and the convection current. or currents controlled as to direction of flow in such a manner as to vcause them to circulate by gravity along well defined paths and in sheet-like currents enveloping the exterior surfaces of one or more chambers located in zones or compartments remote from the chilling unit, and in which higher temperatures are desirable, to provide spacing means for not only separating one or more storage chambers from the insulated walls of the cabinet, but for directing the'convection currents along said delined paths of circulation; to utilize some of the spacing devices as sealing means for excluding the convection currents from the interior of the chamberor chambers which they envelop; and in general to provide means whereby the development of eddies, counter-currents and dead spots may be avoided and circulation accelerated in a manner to promote uniformity in the maintenance of the desired temperatures in all parts of the refrigerator.

In the drawings: i

Figure'l is a front elevation of a refrigerator embodying my invention, with parts broken away vto disclose constructional details.

. Figure 2 is an elevational section, drawn to line 22 of Figure 1.

Figure 3` is a view, partly in elevation and partly in section, drawn to line 3-3 of Figure 2.

any limitation of the scope of the invention as defined in the respective claims.

In Figures 1 to 5, inclusive, I have illustrated a refrigerator of the domestic type having a cabinet provided with a lower compartment Ill for the motor and compressor, an intermediate compartment Il which houses a storage. chamber, and an upper compartmentr I2 which houses a chilling unit and one or more chambers for meat and other foods requiring low temperatures for prolonged preservation. The walls of the compartments II and I2 are insulated, any ordinary insulation being used as indicated at I3.

. The compartment I2 has a non-corrosive lining I4, preferably of metal or porcelain, and its bottom wall has Aslots I5 and I6 along its side and rear margins (Figure 4). Said bottom wall otherwise serves as a partition between the compartments II and I2,both of which have doorway openings at the front which may be closed by a single door Il, although it is immaterial to the invention herein disclosed whether the compartments have separate doors or Whether they are both closed by a single door. f

Y A food storage chamber I8, open at the front, is mounted in the compartment II, from the v walls of which it is spaced by chamber supporting and current controlling bars I9, sealing bars 20, and vertical current controlling bars 2| and 22. 'I'he sealing bars 20 extend along the front margins of the bottom, side' kand top walls of the storage chamber I8 and may be hermetically sealed to these walls and to the -walls of the inwardly underneath the bottom of the chamber I8 between the bottom sealing bar 29 and the inwardly extending legs of the supporting bars I9,

and are then guided by the rearwardlyextending legs of the supporting bars I9 to the rear passages between the vertical spacing bars 22, as shown by the arrows in Figure 5. The currents which descend along the sides of the chamber I8 between the middle and rear side bars 2I are guided into the rear passages across the bottom corner spaces defined by the bars I9. The number of spacing and guiding bars to be employed will depend upon the size of the refrigerator.

The width of the respective convection currents is sumciently limited by these bars to prevent the ,development of eddies, counter-currents or dead spots, to an extent which would otherwise impair the eiiiciency of the refrigerator or the uniformity of the temperature in th chamber which these currents envelop. i

The top of the chamber I8 is covered by an insulating slab v29 from which the lining I4 of compartment I2 is supported by spacing bars or strips 24, preferably of the same l. shape or angular form as the bars I9 in Figure 3. The space between the bottom of the lining I4 and the slab 29 is in communicationwith the above mentioned passages, as best shown in Figure 4, so that the currents across the top of the food chamber I 8 are the exact opposite of the currents across the bottom (see arrows in Figure 3 and Figure 4, respectively).

As shown in Figure 1, the chilling unit is located midway between the side walls of compartment I2. It includes a quick freezing chamber 28 open at the front and encircled by a helically wound evaporator coil 29 of ordinary type, and it is flanked by chambers 30 and 3|, also open at the front, and adapted to receive various food, such as are usually kept at low temperatures. The chamber 28 and one or both of chambers 9| and 29 may be Anormally closed by a shutter or door 92 to prevent complete change of air in the convection system when the main door I1 is open, assuming that a single door I1 is used for both compartments. The openings at. I 5 and I9 permit the convection currents to circulate in part into and out of chamber I2 in shunt respecting the circulation paths shown in Figure 4.

Air flows across the top of the chilling unit in the direction of the sides of the compartment, being guided` to some extent by the evaporator coils.` It descends by gravity through the slots I5 into the channels between the spacing bars 20 and 2|, and then passes underneath the chamber Il to the back wall channels in the manner above described.

In the back wall channels a portion of the air passes upwardly through the slots I9 into the compartment I2, where it-flows forwardly over the chilling unit and the associated storage chambers and then divides and again ilows downwardly along the sides of the compartment through the slots [5. The slots I5 are longer .2,289,662 I than the slots I8, or otherwise made of greater capacity. There are two slots I 5 on each side and four slots I6 along the back wall. Since the slots I9 are of less capacity, some of the returning air.is deflected forwardly over the slab 23 and guided by the spacing bars 24 to the respective side channels to be mingled with the descending currents. The bars 24 are similar in form to the bars I9 and therefore keep the deilected airsubdivided for substantially equal delivery into the descending streams.

In the embodiment illustrated in Figures 6, 7 and 8, the compartment I2a contains two quick freezing chambers 29a and 28h, one on each side of a central storage chamber 30a. An evapora'- tor coil 29a is wound a plurality of turns on the chamber 28a and then extended, as indicated at 59, over the storage chamber 30a, to be wound a plurality of turns upon the freezing chamber 29h and then extended under the storage chamber for a further winding upon the freezing chamber 28a, the windings upon the respective freezing chambers being thus alternated throughout their length. i

In this construction the two freezing chambers and'their coils are located in close proximity to the side walls of the cabinet, thereby not only separately chilling the currents descending along their respective side walls, but more efficiently dividing the air above these coils and above the chamber 30a into two cyclic streams descending along the respective sides of the refrigerator. The rate of circulation may thus be increased over that prevailing in the structure shown in Figure 1.

Also, in this modified construction the forward margins of the quick freezing chambers and those of the storage chamber 30a. are sealed to each other and to the compartment lining I4 by sealing strips 55. These sealing strips have their outer margins connected with the margins of the lining wall I4 around the main doorway opening, thus not only excluding the convection currents from the chambers, but also preventing air from entering the passages when the main door is opened,

It wiu be noted that in'each of the construe-- tions illustrated the quick freezing chambers and associated storage chambers have their longitudinal axes extending from front to rear, and the evaporator coils therefore tend to guilde the convection currents laterally. The entire weight of the inner wall or lining of the compartment I2 is not wholly carried upon the spacing bars 24 but is marginally supported bythe. vertical seal-y ing and guide bars 20, 2I and 22. 'Therefore the' descending currents are maintained in well dened paths by the guide bars at all points, thus assuring the complete and uniform cooling of all side walls of the storage chamber I 9. 'I'he subdivided streams may be allowed to commingle during the return flow, as shown, if desired.

If will lbe noted that the back wall of the cabinet is provided with a removable' section 59 which facilitates installation of the liner I4 with 'the chilling unit and its associated chambers installed therein. The back wall section 59 has a cavity for reception of an ordinary expansionv valve, conventionally indicated at 60, and which may, if desired, be used to control deliveries to the evaporator tube, the inlet end 62 of. which is shown in Figure 2 as extending through the wall of the liner I4. A casing 6I extending vertically along the rear wall of the cabinet may house the supply and return connections between the evapchamber.`

orator Lcoil and a condenser compressor assembly in the lower chamberV I l.

. In the yconstruction shown, the main, door Il "may, if desired, `be used to seal all of the chambers inccmpartment lI2 when this door is c1osed.`

In each of the constructions illustrated there -wil1 be, air` currents inthe food chamber I8, cre- A ated by temperaturefdiierentials between difierent wall p crtionsythereof according as such wall portions'are contacted by the colder or warmer I8 will tend `to follow the `same direction as the lair currents externally of chamber I8, and will lbe equally well distributed throughout the food At the same time thefood in chamber I 8 will retain its moisture, for the reason that thelair circulating inA that chamber is nowhere lj exposed to any surface which has temperatures 4f'lce'lfowfthe freezing point of water and hence would not tend to accumulate'frost. The elimination ofthe dehydrating eilect from the main food storage chamber is a very important and 'desirable characteristic of the improved structure, and it is significant that inthe present device this r'esult is secured while still maintaining the desirable and effective distribution of` well established currents of convection air circulation within the chamber. I

Itis also important that in my improved structures multiple temperatures are attained in a very economical and simple manner without requiring multiple temperature evaporator coils or separate temperature controls.

While my drawings show a complete liner im- Y mediately withinthe insulationv I3 for the purpose of protecting such installation from moisture, it will be understood thatin the preferred arrangements, whereby the .air `or otherlgas'es circulating as convection currents are completely hermetically sealed within the convection space, no accumulations of moisture are ordinarilypossible, and this additional liner may be omitted where it is unnecessary.

l. In a refrigerator, the `combination of a heat l insulated cabinet having a food chamber disposed therein and spaced from the cabinet walls to permit circulation of convection currents along margins to allow` communication between thev chilling unit compartment and the space surrounding the food chamber, means for subdividing and directing convection currents in thin of"by current directing guide strips subdividingA f said space into passages for convection currents,

a chilling unit in the upper compartment, and sealing strips confining the convection currents to the upper compartment and said passages, the bottom wall of said upper compartment having marginal openings along its side and rear portions in registry with the respective passageways at the sides and rear of the food storage chamber,4 the rear openings being of less .capacity than those at the sides, and each rear passage having a by-pass connection with a side passage through one of the top passages. whereby portions of the return ow may be passed over the chilling unit and other portions by-passed while maintaining substantially equal distribution and temperature regulation about the storage chamber. 3. In a refrigerator as set forth in claim 2, a

chilling unit provided with transversely extending refrigerator coils adapted to aid in directing i the chilled convection currents downwardly in said side passages.

4. A refrigerator cabinet having superposed compartments separated by a wall having slotlike openings along its side and rear margins, a chilling unit in the upper compartment adapted to deliver convection currents in substantially equal volume downwardly through the openings along the side margins of said Wall, a food storage chamber in the lower compartment, sep-- being sealed for permanent retention of the convection currents.

5. The combination with a refrigerator cabinet havmg a frontdoor and side, back, top and bot- I tom walls, of a food chamber connected to said cabinet about said door and having side, back, top and bottom walls spaced from the corresponding walls of the cabinet, a chilling unit within the cabinet in the space between the top Wall of the cabinet and the top wall of the food chamber, and supporting and spacing means positione ing the food chamber within the cabinet and streams of denite width downwardly fromthe chilling unit compartment along the sides of the food chamber and underneath its bottom to the space between the food chamber and the back Wall of the cabinet, said back wall space allowing a return iiow to the chilling unit compartment, and guide strips between the bottom wall of the chilling unit compartment and the top ofthe food, chamber defining horizontal passageways therebetween, lsaid guide strips having portions extending from said back wall space forwardly and laterally for directing portions of the currents ascending along the back wall to the streams o =2. A refrigerator cabinet, having in combinay descending along the sides of the food chamber.

tion a set of superposed compartments, afood storage chamber in the lower compartment spaced deiining passageways for the circulation of convection currents upon predetermined paths about the food chamber, said spacing means comprising substantially upright guides between the respective side wallsv ofthe food chamber and cabinet, and guides between the bottom walls of the food chamber and cabinet extending inwardly and rearwardly from the guides rst mentioned,

whereby convection currents descending along the side walls of the food chamber and separated by said guidesl will be directed upon different paths across the bottom of the food chamber and toward the back thereof, the space between the back walls of the food chamber and cabinet `providing a return passageway for ascending convection currents communicating with currents moving. at both sides of the respective bottom g-uides, whereby such currents are merged during their return in the last mentioned passageway.

6. In a refrigerator, a cabinet comprising top,

bottom, side and back walls and a. front door,

supporting guides extending inwardly and rearfrom the top, side,` bottom and rear walls there-l 75 wardly from intermediate portions of the respecc 4 4 l tive side walls across the bottom wall of the cabinet and toward the rear wall thereof, lateral guides upright against the side walls of the cabinet and substantially contacting .the respective supporting guides, a food chamber having a bottom wall resting upon the supporting guides for spacing from the bottom w-all of the cabinet and having side walls laterally contiguous to the lateral guides and spaced' thereby from the side walls of the cabinet, said food chamber having a back wall spaced from the back of the cabinet and a top wall remote from the top wall of the cabinet, top guides upon the top wall of the food chamber corresponding in general location to the supporting guides therebeneath and extending inwardly and rearwardly from said lateral guides, means spacing the rear wall of the food chamber from the rear of the cabinet, and` a chilling compartment within the cabinet above the food chamber and having a. bottom spaced from the food chamber and resting upon said top guides andprovided with air circulation openings communicating with the spaces between theside and back walls of the cabinet and chamber.

7. The device of cl'aim 5in which the guides between ,the bottom walls of the cabinet and food chamber are approximately L-shaped in plan, extending toward each other from the sides of the cabinet and thence sharply rearwardly in mutually spaced relation. 1

8. The device of claim 5 in which the chilling 'unit therein mentioned comprises a pair of `evaporator elements adjacent opposite sides of the cabinet and a freezing chamber in` operative as-l side by side, and a unitarily functioning evapo-l rating means Ienveloping said chambers, said *chambers/ having access openings adjacent the chamber intervening between said sharp freezing Y front of said cabinet and walls connected with said cabinet about said openings, whereby to con- 4 fine convection currents within the cabinet.

10. 'I'he structure of claim 5 in which the chiliing unit comprises sharp freezing chambers adjacent the sides of the cabinet and an interveningfrozen storage chamber and a unitarily functioning evaporator means including portions directly associated with the respective sharp freezing chamber and other portions connecting said first mentioned portions above and below said frozen storage chamber, the respective chambers having access openings adjacent the front of the cabinet and walls connected with the cabinet about said openings whereby to confine withinto said cabinet about said door and having side,

back, top and bottom walls spaced from the corresponding walls of the cabinet, a pair of sharp freezing chambers adjacent the sides of the cabinet between the vtop wall of the food chamber and the topl wall of the cabinet, a frozen storage chambers; means for supporting the several chambers Within the cabinet while accommodating convection currents of air moving down the side walls of the cabinet and up the back wall thereof, and evaporator means comprising portions concentrated adjacent the respective sharp freezing chambers, whereby to accelerate downward air convection, said evaporator portions being in connection across said frozen storage chamber.

12. The device of claim 1l in which said evaporator comprises .a tube having successive coils alternately disposed about said sharp freezing chambers and connected -by intermediate lengths passing above and below said frozen storage chamber..

` GEORGE O. R. LINDGREN. 

